Process of making smokeless explosives



(No Model.)

2 Sheets-Sheet 1. F. G. DU PONT. PROCESS OF'MAKING SMOKELESS EXPLOSIVES.

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im/ray (5421406. .292 M6 (No Model.) 2 SheetsSheet 2. P. G. DU PONT. PROCESS OF MAKING SMOKELESS EXPLOSIVES.

Patehted Aug. 22, 1893.

UNITED STATES PATENT ()FFI'CE;

FRANCIS o. DUPONT, or WILMINGTON, DELAWARE.

PROCESS OF MAKING smoxsu-zss EXPLOSlVES.

SPECIFICATION forming of Letters Patent No. 503,587, dated August 22, 1893.

Application fllodApr i115,1893. Serisllio.470.549. (No specimens.)

To all whom it. may concern:

Be it known that I, FRANCIS G. DUPONT, a citizen of the UnitedStates, residing at Wilmington, in the county of New Castle and State of Delaware, have invented certain new and useful Improvements in Explosives; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others'skilled in the art to'which it appertains to make and use the same.

- My invention relates to improvements in explosives, to be used in guns, as a bursting charge for shells, or for any other explosive use to which it maybe suited, and it consists in the improved process for producing an explosive from nitrocellulose, byagitating therewith, when suspended in a-liquid, in suitable proportions,

an emulsion of a solvent of the same in a suitable liquid, and subsequently hardening the grains thus produced, which will be hereinafter fully described, and particularly pointed out in the claims.

In the joint application of myself and Pierre I S. du Pont for Letters Patent for improvements in explosives, filed December 21, 1892,- Serial No. 455,901, a process for producing a smokeless explosive was described, the distinguishing feature of which consisted in the granulation of the nitro-cellulose by agitating therewith, when'suspended in a suitable fluid, a solvent of the same in proper proportions. Basing the process on the tendency which was found to be inherent in the solvents of nitro-cellulose, and especially the nitro-derivatives of -the aromatic group, when mixed with a fiuid in which finely-divided nitro-cellulose is suspended, to seize the nitro-cellulose and leave the fluid clear, fluid a more or less coherent mass, it was discovered that when the solvent is added in proper proportions, (and the proportion of three parts by weight of the solvent to .one of the nitro-cellulose was found to be a good working proportion,) andthe mass is slightly agitated a well defined granular condition was the result, the solvent collecting the particles of nitro-cellulose into grains, and f0rming a coating around the same. These grains, after they have undergone a process of hardening by rotation in a barrel, and removal of excess of solvent and water contained in A.

small arms, largeforming in the.

the grains byboiling, rel in-an atmosphere of steam, in which case the removal of the excess of solvent and water contained in the grains will take place at the'same time as the rotation, become sufficiently firm to be graded as to size preparatory to being put upon the market, and constitute a valuable smokeless powder, the vio-.

lence of whose explosive action can be diminished by varying. the duration of the above processes, or can be still further diminished by the addition of a substance to moderate its action. For this latter purpose nitrated resin and nit'rated turpentine, i. e., rosin or Venice turpentine treated with nitric acid,were found to be especially suited, and theywere added in the manner and proportion stated in said application.-

The essential feature of the above process,

and that which determines the character of or by rotation in a bar-.

the explosive produced, is the granulation of r the nitro-cellulose. This granulation iseffected, in the process described in said application, by pouring nitro-benzole, or other solvent of nitro-cellulose, into a churn in which a quantity of finely divided nitro-cellulose is suspended in a suitable. liquid, said nitrocellulose having been uniformly distributed through said liquid by the action of thecharm After the solvent has been added to the mixture in the churn, the agitation of the contents'of the same is continued, until the nitro-cellulose has been deposited in the bottom ofthe churn in the form ofgranules, which are somewhat ,pulpy, as they contain in the fiber of the nitrocellulose considerable water, and as there is an excess of solvent in connection with the same.

It is of the utmost importance, in determining the characteristics of the grains produced, that the granulationbe uniform, and that all of the nitrocellulose be precipitated, as.'

otherwise there is a loss of material, and the grains formed are uneven in structure.

I have discovered that complete and uniform granulation of the intro-cellulose may be eifected by emulsifying the nitro-benzole, or other solvent of nitro-cellulose used, before" adding the said solvent to the mixture in the churn, with a suitable liquid. 'Water may be used as such liquid, and may either be pure, or may have in solution in it any of the use of the emulsion thus produced a more uniform granular condition is brought about, and also a more uniforman'd perfect prc'cipitation of the nitro-cellulose obtained, than when the unemulsifiedsolvent is used.

In the drawings accompanying and forming a part of this application, I have represented the apparatus which I use to carry out my process, Figure 1, which is taken on the line ma: Fig. 1, looking in the direction of the arrow, illustrating the churn in which the mixture of the nitro-cellulose with the solvent takes place; Fig. 1 being a sectional view of the same; and Fig. 2 being a representation of the rotating barrel in which the grains 'so that the steam will be formed in the ened and rounded, and thus fitted for use. It is taken on the line 3 y Fig. 2. Fig. 2 is a view taken on the line 2 z Fig. 2, looking in the direction of the arrow. "It shows the double series of apertures in the inner bulkhead of .the barrel, and also the series of cycloidal chutes which conduct the water of condensation, received through the outer series of apertures in the bulkhead, to the aperturesin the central pipes forming the axis of the barrel by which the said water is conveyed away.

Before proceeding with a description of my process, I will describe the apparatus used in carrying it out. v v Referring to Figs. 1 and 1, A represents a churn, "in which, by a shaft are rotated the blades 6, each of which is. formed with a notched outer surface to promote currents from side to side in the contents of the churn during rotation. Steam inlet pi pesC are provided, which are relativelysmallin diameter, well distributed through the contents of the churn, and a single steam outlet pipe D, which leads to the refrigerating coils E, where the vapors which it conducts maybe condensed. An opening in the supports i 2',

F is provided for the admission of material,

and an opening 0' to aid in flushing the in-' terior of the churn when desired. Testoocks l l are also provided, in order that the condition of the contents of the churn may at any time be inspected. r In Figs. 2 and 2, the rotating barrel is represented in which the grains of explosive produced in the churn just described are hardened and prepared for use. This barrel, H, is provided with a tubular axis I, jonrnaled ducted by the pipe 2, and from which steam is conveyed away by the pipe 3. This barrel is designed to facilitate the escape of both steam and water, the former carrying off the solvent used, and'to'this end is formed with an inner bulkhead K, which is placed in close proximity to the bulkhead II of the barrel. In this innerbulkhead are formed two series of apertures, one around its periphery 8, for

churn shown in Fig. 1 are hardto which axis-steam is conthe separation of water from the contents of the barrel, and one near its center 9, for the escape of steam from the same. Between the .two bulkheads K and ll are arranged a series of cycloid'al chutes or guides L, all of which converge toward the central axis. In the'operation of the barrel, steam is admitted to its interior through the apertures 9 in thebulkhead K, from whence it passes through the axis I and the pipe 3. -W-'ater of condensation, asfast as formed, passes through the outerseries of apertures in the bulkhead K at the lower part of revolution of the barrel into the space between said bulkhead and bulkhead H and is conducted by the cycloidal chutes toward the axis of the barrel, then passing out through the apertures 6 formed at this point. v

Proceeding now with nay-process, I place in the churn A. about ninety liters of water, or other liquid, which may either be pure, or mixed with any salt. hen water is used, I sometimes dissolve in it chloride of calcium, common salt, saltpeter, or other salt, as the characteristics of the grains produced can thus be modified in many ways. I thenadd to the water about six kilograms of nitrocellulose, beating it up with the waterin the churn until a thorough mixture has taken place. In another churn similar to that shown in Figs.1 and 1, or in any other suitable machine,'I prepare an emulsion of the solvent of the nitro-ccllulose which I- desire to use with water, or with other emulsifying liquid. When water is used, I add it to the solvent, such as nitro-benzol'e, in about the proportions of three times the weight of thenitrobenzole. When carbonate of soda liquor is used, I add one pound of the carbonate of soda to a gallon of water, and use about the same weight of liquor as in the case of pure water. When soap is used to aid emulsion, I add it in the proportion of about one ounce to twenty-five pounds of nitro-benzole, and use about the same weight of water 'as be- I do not restrict myself to the use of the emulsifying agents above mentioned, stating them merely as examples, nor to the proportions here to the solvent of the nitrocellulose, or those in which the various ingred to water. The emulsion thus produced is added to the mixturefin churn A, a suflicient.

tents are added stated of adding the same -benzole, or other solvent I nitro-cellulose into 3? 1 formed preventing" the grains from becoming'attached to each other, or otherwise forming one mass. The

action of the solvent when emulsified in the manner above stated is much more rapid and complete than when such solvent is added in an unemulsified form, and results in the more perfect granulation hereinbefore described. The grains thus formed, when removed from the churn, may be treated with steam to remove the excess of solvent and.

the water contained in the grains, and then ,be used with success for some explosive uses,

described in the joint application of myself and Pierre S. duPont above referred to, by rotating the barrel for a greater or less time without the admission of steam, until the grains are compacted and rounded, then filling the barrel partially with water, and rotating it with admission of steam in such a di- 'rection as to prevent the water from being carried away, and then changing the direction of rotation and continuing the flow of steam until the solvent is entirely removed; or in the manner described in the joint application of myself and Pierre S. du Pont filed March 17, 1803, Serial No. 466,488, in which the grains are, at some time before their final rounding and compacting treated with heat, but of a degree below that of the point of vaporization of the solvent used in the production of the grains, to remove more effectually the watercondensed in the fibers of the grains. The latter method of treatment is preferred, as resulting in a more finished product. The explosive force of the grains thus produced may be tempered in explosive force to any degree required by the addition of a suitable moderating agent, in the manner described in the joint applications before referred to.

While I have described the nitro-cellulose as being diffused in water, it is evident that any other fluid which will cause a better, or as good a-distributionof the nitrocellulose in tho churn may be used instead.

I do not confine myself to the exact propor- I tions used, nor to the particular apparatus described, as these can be varied and changed without afiecting the merits of this invention. What I claim'as-new,'and desire to secure by Letters Patent, is'- l. The herein described process of producing a smokeless explosive, which consists in suspending nitro-cellulose in a liquid not a solvent of the same, granulating the nitrocellulose by agitating therewith in proper proportions an emulsion of a solvent of the nitro-cellulose, which is not miscible to any great extent in the liquid used to suspend the same, in a suitable liquid in proper-proportions, and

solidifying the grains thus formed, substantially as described.

2. The herein described process of producing a smokeless explosive, which consists in suspending nitro cellulose in a liquid not a solvent of the same, granulating the nitrocellulose by agitatingtherewith in proper proportions an emulsion of a solvent of the same, which -is not miscible to any great extent in the liquid used to suspend the nitro-cellulose, with water in proper proportions, and solidi-' fying the grains thus formed, substantially as described.

3. The herein described process of.producing a smokeless explosive, which consists in suspending nitro-cellulose in a liquid not a solvent of the same, granulating the nitrocellulose by agitating therewith in proper proportions-an emulsion of nitro-benzole, which is not miscible to any great extent in the liquid used to suspend the nitro-cellulose, with a suitable liquid in proper proportions, and solidifying the grains thus formed, substantially as described.

In testimony whereof I aihx my signature in presence of two witnesses.

" FRANCIS G. DU PONT.

Witnesses: I

FRANCIS I. DU Pour, ELIZA Saxons. 

